A Question About Volume Controls Types

My previous preamp's volume knob had a definite low point and high point. When it was powered down I could rotate the volume up to the maximum setting and if I left it there and switched the preamp on, it would of course come on at full volume.

I'm trying to understand how the volume control works on my McIntosh MA252 integrated amp. When it's turned off and I spin the volume control up, there's no end point; it just free wheels. After I've done that and I power it up, the volume is exactly where it was during my last listening session.

Can someone explain how they work so differently?